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Biomedical subjects

P J Bucher

Publications and source records attributed to P J Bucher.

7 recordsLinked to original sources
PubMed1995

Dystrophic calcification of an implanted hydroxyethylmethacrylate intraocular lens.

Hydroxyethylmethacrylate is a biomaterial still under clinical trial for use in foldable intraocular lenses. We observed a patient in whom a geographic opacification developed within an implanted hydroxyethylmethacrylate lens, together with granular deposits on the posterior lens capsule and in the scar of a paracentesis. The intraocular lens and posterior lens capsule were removed because of impaired visual acuity. Light and scanning electron microscopy disclosed nodular calcifications within the intraocular lens and granular, partially crystalline, calcifications on the posterior lens capsule. Energy-dispersive x-ray analysis and x-ray diffraction showed the deposits in the intraocular lens to consist of calcium hydroxyapatite. We presume this mineralization to be dystrophic, with calcium derived from lens remnants and phosphorus possibly derived from a thymoxamine solution used briefly during the cataract operation. Our observation suggests caution in the use of phosphated solutions together with hydroxyethylmethacrylate intraocular lenses and may warrant reconsideration of the suitability of hydroxyethylmethacrylate intraocular lenses, should additional similar cases be reported.

Aged↗
PubMed1994

High-resolution perimetry of the central visual field.

The Octopus Program M1 was designed for the detection/follow-up of central or paracentral visual field defects in patients with neurological disorders or with macular or perimacular diseases. Within the central 25 degrees visual field, 59 test locations provide a resolution of < or = 1.4 degrees. The differential light sensitivity is measured with 'Octopus normal strategy', i.e. a 4/2/1 staircase procedure. The Program M2X has 81 test locations in the central 10 degrees, giving even higher resolution (< or = 0.7 degrees) of the central visual field. Both programs have 2 phases, the second being a re-test. Program M2X's phases are divided into 4 stages and allow interruption anytime.

Adult↗
PubMed1990

Anterior chamber depth with sulcus and capsular bag placed IOGEL lenses.

The anterior chamber depth was measured in 15 eyes with sulcus placed (Group 1) and 12 eyes with bag placed (Group 2) IOGEL PC-12 lenses, and in 11 eyes with bag placed IOGEL 1103 lenses (Group 3). The mean anterior chamber depth was 3.29 mm in Group 1, 4.17 mm in Group 2, and 4.16 mm in Group 3. The difference between the mean anterior chamber depth with sulcus and bag placed IOGEL PC-12 lenses is statistically significant (P less than .0005). One effect of the different anterior chamber depths was that the anterior surface of a sulcus placed IOGEL lens frequently touched the pupillary border, whereas this rarely occurred when it was placed in the capsular bag. Another effect of differing anterior chamber depths was a different A-constant for the SRK-formula for sulcus or bag placement. In this study it was about 1 diopter greater with bag fixation than with sulcus fixation. It is recommended that each surgeon use specific A-constants to enhance the predictability of the postoperative refraction.

Aged↗
PubMed1990

[3 years' clinical experience with IOGEL lenses].

A total of 63 IOGEL PC-12 and 12 IOGEL 1103 intraocular lenses have been implanted at Lausanne and Basle University Eye Hospitals, and followed up for up to 3 years. In general, the functional and anatomic results are good. From a comparison of the behavior of IOGEL lenses implanted in the sulcus and capsular bag it is concluded that given a suitable surgical technique the IOGEL 1103 lens with implantation in the capsular bag may be recommended.

Acrylates↗
PubMed1989

One year follow-up of IOGEL intraocular lenses with ciliary sulcus fixation.

Fifty-one soft hydrogel posterior chamber intraocular lenses (IOLs) were implanted in the ciliary sulcus after planned extracapsular cataract extractions. In nine cases the IOLs were positioned with one haptic in the capsular bag and the other in the ciliary sulcus. During a one-year follow-up, Nd:YAG capsulotomy was performed on five eyes and cystoid macular edema was present in two cases. No other serious complications were encountered. At one year, visual acuity was 20/30 or better in all eyes that did not have preexisting secondary eye problems. To prevent postoperative rotation, decentration, and deformation of the IOL, unnecessary intraocular manipulation and "in-out" positioning of the IOL should be avoided.

Aged↗
PubMed1988

Prevalence and causes of blindness in the northern Transvaal.

During November 1985 a survey was carried out to determine the prevalence and causes of blindness in the Elim Hospital district of Gazankulu in the Northern Transvaal, South Africa, and to assess the Eye Department's effectiveness in preventing blindness. Using a random cluster sample technique, we screened 18,962 of the estimated 71,200 inhabitants of the district (26.6%). We found 109 blind people. The prevalence of blindness was 0.57% (95% confidence interval 0.46%-0.68%). The main causes of blindness were senile cataract (55%), corneal scarring due to trachoma (10%), uncorrected aphakia (9%), and open-angle glaucoma (6%). There were 14 aphakic blind persons who did not have aphakia glasses (43% of all persons operated on for cataract). Women had a significantly higher prevalence of blindness than men. After the age of 60 years the prevalence of blindness increased sharply. Women were 1.6 times less likely to have undergone cataract surgery than men. The two most effective steps to reduce the prevalence of blindness in the Elim district further are to provide aphakia glasses to all aphakic patients and to improve the accessibility of the Eye Department's surgical services.

Adolescent↗